CVE-2021-27517: Foxit PDF SDK For Web through 7.5.0 allows XSS

Q: How do I fix CVE-2021-27517?

phantompdf: upgrade to newer than 10.1.3.37598; reader: upgrade to newer than 10.1.3.37598. Exact commands for each OS are on this page.

Q: Is CVE-2021-27517 being exploited?

CVE-2021-27517 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-27517 affect?

CVE-2021-27517 affects phantompdf, reader. Severity is medium (CVSS 6.1). Foxit PDF SDK For Web through 7.5.0 allows XSS. There is arbitrary JavaScript code execution in the browser if a victim uploads a malicious PDF document containing embedded JavaScript code that abuses app.alert (in the Acrobat JavaScript AP

Q: How urgent is CVE-2021-27517?

Priority 35/100. No elevated risk signals yet.

Routine

MEDIUM 6.1UPGRADEUPGRADE

CVE-2021-27517 is a medium-severity flaw (CVSS 6.1) affecting phantompdf, reader. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Foxit PDF SDK For Web through 7.5.0 allows XSS. There is arbitrary JavaScript code execution in the browser if a victim uploads a malicious PDF document containing embedded JavaScript code that abuses app.alert (in the Acrobat JavaScript API).

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.8% (top 44%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-07-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: foxit

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-07-20 12:15 UTCPublished CVE record published
2026-06-17 03:45 UTCUpdated Record last modified

foxit phantompdf UPGRADE

Affected: <= 9.7.5.29616 · >= 10.0.0.0 and <= 10.1.3.37598

Fixed in: newer than 10.1.3.37598

Safe to downgrade to: a release before 10.0.0.0

1. Check installed version

apt-cache policy phantompdf || rpm -q phantompdf || phantompdf --version

2. UPGRADE to newer than 10.1.3.37598 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade phantompdf

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade phantompdf

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 10.0.0.0 (Debian / Ubuntu)

apt-cache madison phantompdf sudo apt install phantompdf=<VERSION_BEFORE_10.0.0.0> sudo apt-mark hold phantompdf

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list phantompdf sudo dnf downgrade phantompdf-<VERSION_BEFORE_10.0.0.0> sudo dnf versionlock add phantompdf

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

foxit reader UPGRADE

Affected: <= 10.1.3.37598

Fixed in: newer than 10.1.3.37598

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy reader || rpm -q reader || reader --version

2. UPGRADE to newer than 10.1.3.37598 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade reader

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade reader

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-27517?

phantompdf: upgrade to newer than 10.1.3.37598; reader: upgrade to newer than 10.1.3.37598. Exact commands for each OS are on this page.

Is CVE-2021-27517 being exploited?

CVE-2021-27517 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-27517 affect?

CVE-2021-27517 affects phantompdf, reader. Severity is medium (CVSS 6.1). Foxit PDF SDK For Web through 7.5.0 allows XSS. There is arbitrary JavaScript code execution in the browser if a victim uploads a malicious PDF document containing embedded JavaScript code that abuses app.alert (in the Acrobat JavaScript AP

How urgent is CVE-2021-27517?

Priority 35/100. No elevated risk signals yet.

Software pages

Adobe Acrobat vulnerabilities

Related CVEs

CVE-2022-25641 MEDIUM 5.5 UPGRADE UPGRADE Foxit PDF Reader before 11.2.2 and PDF Editor before 11.2.2, and PhantomPDF before 10.1.8, mishandle cross-ref
CVE-2021-41785 HIGH 7.8 UPGRADE UPGRADE Foxit PDF Reader before 11.1 and PDF Editor before 11.1, and PhantomPDF before 10.1.6, allow attackers to trig
CVE-2021-41784 HIGH 7.8 UPGRADE UPGRADE Foxit PDF Reader before 11.1 and PDF Editor before 11.1, and PhantomPDF before 10.1.6, allow attackers to trig
CVE-2021-41783 HIGH 7.8 UPGRADE UPGRADE Foxit PDF Reader before 11.1 and PDF Editor before 11.1, and PhantomPDF before 10.1.6, allow attackers to trig
CVE-2021-41782 HIGH 7.8 UPGRADE UPGRADE Foxit PDF Reader before 11.1 and PDF Editor before 11.1, and PhantomPDF before 10.1.6, allow attackers to trig

References

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